System and method for performing lossless switching in a redundant multicast network

Abstract

A system and method is provided for performing lossless switching in a redundant multicast network. An exemplary method includes receiving a primary media stream and a redundant media stream over different forwarding network paths by network ports of a receiver communicatively coupled to an A/V device. Furthermore, the receiver outputs media data of the media streams to the A/V device to be presented thereon. In response to a control signal to switch the receiver to a new primary media stream, the method disconnected either the primary ort the redundant media streams from the respective network port of the receiver receiving that stream. Furthermore, the method includes controlling the disconnected network port to receive the new primary media stream and then outputting media data of the new primary media stream to the A/V device to be presented thereon.

What is claimed: 
     
       1. A media stream switching system for performing lossless switching of media streams having redundancy without increased bandwidth consumption, the media stream switching system comprising:
 a receiver having at least first and second recorder channels each having a network port for respectively receiving at least one media stream; 
 a media stream input controller configured to control the first and second recorder channels to respectively receive primary and redundant data streams of first media data over different forwarding paths of a multicast network; 
 a media stream redundancy controller configured to store the primary data stream of the first media data in a first media stream buffer and replace lost data packets of the primary data stream with corresponding data packets from the redundant data stream; 
 a media stream output configured to fetch the stored first media data from the first media stream buffer and output the fetched first media data to an A/V device communicatively coupled to the receiver for display thereon; 
 a media stream disconnector configured to initiate a switch of the receiver from receiving the first media data to receiving second media data without increased bandwidth consumption by the receiver by disconnecting the second recorder channel from receiving the redundant data stream; 
 a new media stream controller configured to control the disconnected second recorder channel to receive a primary data stream of the second media data that is configured to be stored in a second media stream buffer; 
 a media stream switcher configured to perform lossless switching of the first media data to the second media data by switching the media stream output to switch from fetching the stored first media data to fetching the second media data stored in the second media stream buffer and output the fetched second media data to the A/V device to be displayed thereon; and 
 a data stream alignment controller configured to store the primary data stream of the second media data in the second media stream buffer upon alignment of the primary data stream of the first media data based on respective RTP time stamps of the data packets of the first and second media data, 
 wherein the media stream disconnector is further configured to disconnect the first recorder channel from receiving the primary data stream of the first media data and the media stream input controller is further configured to control the disconnected first recorder channel to receive a redundant data stream of the second media data to provide redundancy for the second media data. 
 
     
     
       2. The media stream switching system according to  claim 1 , wherein the media stream input controller is further configured to align the redundant data stream of the second media data with the primary data stream of the second media data. 
     
     
       3. The media stream switching system according to  claim 2 , wherein the media stream input controller is further configured to align the primary data streams of the first and second media data by determining that an address of the first media stream buffer has reset and then controlling the respective network port of the second recorder channel to receive the primary data of the second media data. 
     
     
       4. The media stream switching system according to  claim 3 , wherein the media stream redundancy controller is further configured to store the primary data stream of the second media data in the second media stream buffer and replace lost data packets of the primary data stream of the second media data with corresponding data packets from the redundant data stream of the second media data. 
     
     
       5. The media stream switching system according to  claim 1 , wherein the first and second media stream buffers are separate memory banks in a single shared memory. 
     
     
       6. The media stream switching system according to  claim 1 , further comprising a packet parser configured to parse data packets of the respective primary data streams of the first and second media data to identify respective header information and correspond RTP time stamps. 
     
     
       7. A media stream switcher for performing lossless switching of media streams having redundancy, the media stream switcher comprising:
 a media stream redundancy controller configured to store a primary data stream of first media data in a media stream buffer and replace lost data packets of the primary data stream with corresponding data packets from a redundant data stream, wherein the primary and redundant data streams of the first media data are received by a pair of receiver channels over different forwarding paths of a multicast network; 
 a media stream output configured to fetch the stored first media data from the media stream buffer to an A/V device communicatively coupled to the receiver for display thereon; 
 a media stream switch controller configured to disconnect one of the pair of receiver channels to initiate a switch from receiving the first media data to receiving second media data; 
 a media stream alignment controller configured to control the disconnected receiver channel to receive a primary data stream of the second media data and to store the received primary data stream of the second media data in the media stream buffer to be aligned with the primary data stream of the first media data; and 
 a lossless switch controller configured to switch from the first media data to the second media data by controlling the media stream output to start fetching and outputting to the A/V device the stored second media data at a top of a frame of the first media data, such that first media data is cleanly switched to the second media data when displayed on the A/V device, 
 wherein the media stream alignment controller is further configured to store the primary data stream of the second media data in the media stream buffer upon alignment of the primary data stream of the first media data based on respective RTP time stamps of the data packets of the first and second media data. 
 
     
     
       8. The media stream switcher according to  claim 7 , wherein the media stream switch controller is further configured to disconnect a second of the receiver channels from receiving the primary data stream of the first media data and the media stream alignment controller is further configured to control the disconnected second receiver channel to receive a redundant data stream of the second media data to provide redundancy for the second media data. 
     
     
       9. The media stream switcher according to  claim 8 , wherein the media stream alignment controller is further configured to align the primary data stream of the first media data with the primary data stream of the second media data. 
     
     
       10. The media stream switcher according to  claim 9 , wherein the media stream alignment controller is further configured to align the primary data streams of the first and second media data by determining that an address of the media stream buffer has reset and then controlling the respective network port of the second receiver channel to receive the primary data stream of the second media data. 
     
     
       11. The media stream switcher according to  claim 10 , wherein the media stream redundancy controller is further configured to store the primary data stream of the second media data in the media stream buffer and replace lost data packets of the primary data stream of the second media data with corresponding data packets from the redundant data stream. 
     
     
       12. The media stream switcher according to  claim 11 , wherein the media stream buffer is a single shared memory comprising separate memory banks for storing the first and second media data, respectively. 
     
     
       13. The media stream switcher according to  claim 7 , further comprising a packet parser configured to parse data packets of the respective primary data streams of first and second media data to identify respective header information and correspond RTP time stamps.